If everyone smoked twenty cigarettes a day the difference between those who got lung cancer and those who didn’t would be almost 100% heritable, even though the cause would be almost 100% environmental. Heritability depends on our environment.
It is believed that IQ is around 70% heritable, if all children were to have an educationally rich environment in which to grow then, due to this environment, the effect of heritability on IQ would increase. If children were brought up in an educationally damaging environment the effects of heritability on IQ would reduce dramatically.
Tim Spector, Professor of Genetic Epidemiology and Director of the TwinsUK Registry at Kings College, London, says that: “Any change in environment has a much greater effect on IQ than genes.”
Twin Studies are often used to justify arguments around genetic determinism. Spector, who has been studying identical twins for over twenty years, believes that when it comes to commenting on their similarities: “We put much more importance on these things than we should,” he thinks their differences are just as important, though not often commented upon in studies. Genes are possibilities, not a story of what we will become. Our environments help write the stories.
Nature and nurture both have roles to play.
But what of free will? If we are a product of genes and of our environment do we have much of a say in what we do? Who is this ‘I’ whom we refer to? Buffeted by both, it seems we have little to do but blame or thank history, geography and biology.
This is what it comes down to at the moment of choice about something, are we responsible for what we choose to do? You might say you are guided by values, beliefs, by ‘who you are’ and yet people do change their mind about quite fundamental things. Renouncing a religion or political affiliation for example… would this be due to a change in the environment, to what you are reading or who is convincing you? Would you be different if you were born in North Korea rather than South London? Or Hampshire?
If we accept biases we are born with, are we more free to reject them? Are we more open to the feelings and beliefs of others? Or do we hate them for it?
Is freedom of will completely without constraints? What would a person be like who was not in some way a servant of his or her environment and biology? Someone completely free would probably have to be locked up for his or her own good. One minute they would murder, the next they would laugh and cry and compose a symphony, and play it loud at 1 am.
Yet, we know, when we do something that it is the ‘I’ that does it. I am a product of my environment and genes, that I might be a servant to them is one thing. It doesn’t mean I’m a slave.
Do we need schools? Yes. To create a positive environment in which all can flourish, and in which they can realise their freedom. This freedom involves constraints and becoming aware of their importance. That everyone’s environment is different makes a difference, this is where our lived humanity comes into play. In the end a society in which everyone has to smoke twenty a day is, of course, inhuman, but we should aim for everyone to have an education, and a good one. However, were we to receive exactly the same education worldwide that would be inhuman too, although our differences in IQ would be more heritable, what would we have lost?
So teach, learn, and not worry too much about our genes… they make a difference but if you want to make a large difference teach great stuff and teach it well. It can be life-changing and life affirming.
NB: In writing this post I am indebted to the book Freedom Regained by Julian Baggini it is also the source of the quotes.